I use these in my 200 gallon outdoor goldfish pond as a prefilter on my waterfall pump. They go much longer than the original hydro sponges before they need cleaning. Highly recommend.
I’ve used these sponges for about 20 years and they are the best you can buy.They last at least that long because I’m still using a couple of them yet. I’m so glad they’re made to fit the API filters so I don’t have to buy a whole new replacement